Theoretical investigation of electronic, optical and thermoelectric properties of tellurium doped barium titanate (BTO) through modified Becke Johnson exchange potential

TL;DR

This study uses advanced computational methods to analyze how tellurium doping alters the electronic, optical, and thermoelectric properties of barium titanate, revealing potential for improved device applications.

Contribution

It introduces a modified Becke Johnson exchange potential approach to systematically investigate Te-doped BaTiO3's properties, highlighting controllable band gap reduction and enhanced optical absorption.

Findings

Te doping reduces the band gap from 3.692 eV to 1.619 eV.

Doped structures exhibit optical absorption exceeding 10^5 cm^-1.

Electrical conductivity and thermoelectric efficiency are significantly improved.

Abstract

The stability, electronic structure, optical and thermoelectric properties of Te-doped BaTiO3 are investigated by first-principal calculation based on the density functional theory and Boltzmann transport theory implemented in WIEN2K and BoltzTraP simulation program. This study is carried out by applying LDA + TB-mBJ potential. Formation energy of each doped structure is calculated to examine the stability and feasibility of the synthesis. Incorporating Te into BaTiO3 efficiently reduces the electronic band gap and the level of band gap reduction can be controlled by varying the amount of dopant. Hence, the absorption ability is improved in the visible light. Our findings suggest that all the doped structures are significantly absorbent and productive with an optical absorption that exceeds 105 cm-1 in the visible range. In addition, BaTiO3 revealed a smaller dielectric constant at zero frequency compared to Te doped-BTO: 8.3%, while the optical energy gap is reduced from 3.692 eV to 1.619 eV by growing Te concentration. Then, optical conductivity and Urbach's parameters are predicted. The transport properties are assessed as a function of temperature. It is found that the electrical conductivity is considerably enhanced with increase properties such as Seebeck coefficient and figure of merit are also investigated. Our theoretical results can be useful for thermoelectric and visible light photoelectrical device applications.